The present invention relates generally to inkjet printheads, and more particularly to a wide-array inkjet printhead assembly.
A conventional inkjet printing system includes a printhead and an ink supply which supplies liquid ink to the printhead. The printhead ejects ink drops through a plurality of orifices or nozzles and toward a print medium, such as a sheet of paper, so as to print onto the print medium. Typically, the orifices are arranged in one or more arrays such that properly sequenced ejection of ink from the orifices causes characters or other images to be printed upon the print medium as the printhead and the print medium are moved relative to each other.
In one arrangement, commonly referred to as a wide-array inkjet printing system, a plurality of individual printheads, also referred to as printhead dies, are mounted on a single substrate. As such, a number of nozzles and, therefore, an overall number of ink drops which can be ejected per second is increased. Since the overall number of drops which can be ejected per second is increased, printing speed can be increased with the wide-array inkjet printing system.
Mounting a plurality of printhead dies on a single substrate, however, requires precise alignment between the printhead dies. Misalignment between the printhead dies can adversely affect performance of the inkjet printing system. A variation in planarity of the substrate, for example, results in a variation of planarity among the printhead dies and, therefore, misalignment between the printhead dies. Unfortunately, a variation of planarity among the printhead dies can result in ink drop trajectory errors as well as pen-to-paper spacing problems which degrade print quality. In addition, mounting of a plurality of printhead dies on a single substrate requires a plurality of electrical connections between electrical contacts of the substrate and electrical contacts of the printhead dies.
Accordingly, a need exists for precisely mounting and aligning a plurality of printhead dies on a single substrate of a wide-array inkjet printhead assembly such that misalignment between the printhead dies is avoided while an integrity of electrical contacts of the substrate is maintained.
One aspect of the present invention provides a method of forming an inkjet printhead assembly. The method includes providing a substrate, disposing a first planarization layer on a first face of the substrate such that a first surface of the first planarization layer contacts the first face of the substrate, mechanically planarizing a second surface of the first planarization layer opposed to the first surface thereof, and mounting a plurality of printhead dies on the second surface of the first planarization layer. Mechanically planarizing the second surface of the first planarization layer includes reducing a thickness of at least a portion of the first planarization layer.